The number 771
771 is a binary palindrome (1100000011). Its prime factorisation is 3 × 257. Divisors (4): 1, 3, 257, 771.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 771: a binary palindrome (1100000011); a semiprime: 3 × 257, the product of two primes.
- 2
771 is composite. Its prime factorisation is
- 3
The divisors add up to 1032; without 771 itself that is 261, so 771 is deficient (261 is less than 771). Euler's totient φ(771) = 512 numbers up to 771 share no factor with it.
- 4
The digits of 771 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 33 steps to reach 1.
LaTeX source of the formulas on this page
\[ 771 = 3 \times 257 \]
771 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1032 |
| Euler totient φ(n) | 512 |
| Square | 594441 |
| Cube | 458314011 |
| Square root | 27.766887 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 33 |
| Scientific notation | 7.71 × |
771 in other forms
| Form | Value |
|---|---|
| In words | seven hundred and seventy-one |
| Roman numerals | DCCLXXI |
| Binary (base 2) | 1100000011 |
| Octal (base 8) | 1403 |
| Hexadecimal (base 16) | 303 |
| Base 3 | 1001120 |
| As time | 771 seconds = 12 min 51 s |
Is 771 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (771 ÷ 3 = 257) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | No (remainder 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 771 a prime number?
No. 771 = 3 × 257, so it is divisible by 3.
What are the factors of 771?
1, 3, 257, 771.
What is 771 in binary?
1100000011 (hexadecimal 303, octal 1403).
What is the square root of 771?
About 27.7669.
What is 771 in Roman numerals?
DCCLXXI.
Is 771 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 771?
771 is a binary palindrome (1100000011); a semiprime: 3 × 257, the product of two primes.